With just a month to go before Apple’s (NASDAQ:AAPL) annual Worldwide Developer Conference (WWDC) in June, tech enthusiasts around the world are expecting the Cupertino, Calif.-based technology giant to follow past precedent and unveil the next version of its mobile operating system during the event.

While Apple has not yet made anything official regarding a June launch of iOS 7, such a release seems likely now that data from the server logs of some websites showed that Web traffic from devices running the yet-to-be-announced iOS 7 has increased significantly in recent days.

Apple is likely to integrate both Flickr and Vimeo into the upcoming iOS 7.Photo: IBTimes

TechCrunch reported Wednesday that Onswipe, a company that specializes in creating tablet-optimized HTML5 websites for its customers, has observed “a significant bump” in the number of visits to its partner sites -- from both iPhones and iPads that apparently run on iOS 7 -- over the last few days. In fact, there’s been quite a big spike in iOS 7 use from iPhones and iPads, especially those located in Cupertino and San Francisco.

“SF had the most iOS 7 visits, with 18.75 percent, and Cupertino accounted for 17.9 percent of the total,” the report said. “May 2 saw the highest iOS 7 traffic to date, representing 23 percent, or nearly a quarter, of all unique iOS visitors to Onswipe-enabled sites. Most were visiting from iPhones (75 percent), but iPads also represented a full quarter of visits.”

When it comes to Apple’s conventional release procedure for a new OS, the company carries out multiple beta tests of the new version. It first tests the firmware internally and then releases it as a developer preview to the registered iOS developers. After testing the beta versions of the new iOS for a few more months, Apple finally releases it to the public.

With that in mind, an increase in the number of iOS 7 users indeed suggests that the upcoming firmware update is currently under a heavy testing phase, just ahead of a wider launch at WWDC next month.

Apart from Onswipe, some other sites have also witnessed what they believe indicates that Apple’s engineers are ramping up their testing of the new iOS.

MacRumors reported noticing a significant surge in Web traffic from iOS 7 devices in its server logs over the last week. Based on the hits coming from Apple’s block of IP addresses, the report suggests that the iPhone-maker may have started a new phase of testing with the WWDC 2013 approaching rapidly.

A similar spike in Web traffic in recent days has also been reported by AppleInsider. According to the site, while “the number of iOS 7 devices was relatively flat through April 29, appearances of the operating system grew significantly on April 30, and have persisted ever since.”

After analyzing its own traffic logs, Ars Technica has also seen a trend that closely resembles that of MacRumors. However, it noted that “traffic using iOS 7 is still relatively low,” and it’s not surprising either, given that “the OS is only just making its way into usable form.”

“Around April 29-30, visits from devices claiming to be running iOS 7 began to pick up, and the numbers seem to be rising as the days go on,” the report said. “But we're talking about around 100 (or lower) on most days, with only the highest point going up past 100. For us, the large majority of those are on iPads -- we can count the number of visits from iPhones or iPod touches on one hand.”

As for what the new iOS version will offer this time around, a number of earlier reports have suggested that iOS 7 is going to sport a redesigned user interface (UI) and a lot of other notable enhancements. The new UI in iOS 7 is widely expected to be “very flat” and without “all signs of [the] gloss, shine and skeuomorphism seen across current and past versions of iOS.” And all these changes were apparently made under the direction of Apple’s Human Interface team lead Jony Ive.

Rumors are also rife that iOS 7 will feature improved in-car Maps and Siri integration. In addition, core apps, including calendar and email, will receive important functionality updates.